Hirata Y, Fukui K, Hayakawa H, Namba S, Ishimitsu T, Sugimoto T, Kimura K, Matsuoka H, Sugimoto T
Second Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Jpn Heart J. 1990 Nov;31(6):809-16. doi: 10.1536/ihj.31.809.
To further study the mechanisms of the renal effects of ANP, we examined the effects of NaCl loading and ANP infusion on nephrogenous cGMP production. Six normotensives (NTs) and 7 essential hypertensives (HTs) were placed on 7-day low (3 g/day) and then 7-day high NaCl diets (20 g/day). On the last day of each period, the natriuretic and nephrogenous cGMP responses to ANP infusion at 25 ng/kg/min for 40 min were determined. ANP infusion markedly increased the plasma concentrations of ANP and cGMP and the urinary excretions of Na and cGMP. These changes were accompanied by a rise in nephrogenous cGMP. Increases in nephrogenous cGMP during ANP infusion were not different between HTs and NTs despite a greater natriuretic response in HTs. NaCl loading significantly increased the natriuretic response to ANP infusion in both groups. However, nephrogenous cGMP production induced by ANP infusion was not affected by changes in NaCl intake. Thus, although ANP-induced natriuresis is associated with an increase in nephrogenous cGMP, the natriuretic effect of ANP seems to be modified to a greater extent by indirect mechanisms such as renal perfusion pressure and body fluid volume status.
为了进一步研究心钠素（ANP）对肾脏作用的机制，我们检测了氯化钠负荷及ANP输注对肾源性环磷酸鸟苷（cGMP）生成的影响。6名血压正常者（NTs）和7名原发性高血压患者（HTs）先接受7天低钠（3克/天）饮食，然后接受7天高钠（20克/天）饮食。在每个阶段的最后一天，测定以25纳克/千克/分钟的速度输注ANP 40分钟后的利钠及肾源性cGMP反应。输注ANP显著增加了血浆ANP和cGMP浓度以及尿钠和cGMP排泄。这些变化伴随着肾源性cGMP的升高。尽管HTs的利钠反应更大，但输注ANP期间HTs和NTs的肾源性cGMP升高并无差异。氯化钠负荷显著增加了两组对输注ANP的利钠反应。然而，输注ANP诱导的肾源性cGMP生成不受氯化钠摄入量变化的影响。因此，尽管ANP诱导的利钠作用与肾源性cGMP增加有关，但ANP的利钠作用似乎在更大程度上受到诸如肾灌注压和体液容量状态等间接机制的调节。
